Edward the Confessor dies on January 5. He is buried the next day in his new abbey church at Westminster, which has been consecrated only the previous week. On the same day as the funeral there is a coronation, almost certainly carried out in the abbey. Harold, earl of Wessex, named as his successor by the dying Edward, is now king. His reign will last ten months. And it will include a strange omen - a bright long-haired star moving through the sky.

The succession of an earl to the English throne is stimulating news to two neighbouring rulers, across the sea.

Harald Hardraade, king of Norway, ponders a renewal of Scandinavian rule in England. More predictably William, duke of Normandy, makes plans to press his claim to the English throne. As a cousin of Edward the Confessor (whose mother Emma was a Norman), William has closer links with the English crown than Harold. And the pope supports his claim.

For these reasons Harold expects an invasion across the Channel. William is known to be constructing a fleet of longships, so Harold keeps an army in readiness on the south coast. But it is disbanded when its supplies run out in the late summer. And in September an unexpected crisis causes the king to hurry north.

Harald Hardraade has joined forces with Harold's disaffected brother, Tostig earl of Northumberland. A fleet of Norwegian longships appears in the Humber in September. The invaders defeat an English army near York. On September 24 they are welcomed into the city, with its long tradition of links with the Vikings as the Danish capital in England.

The following day, after moving north at speed, Harold surprises and defeats the intruding army at Stamford Bridge. Both Harald Hardraade and Tostig are killed in the encounter. But this satisfactory outcome is soon soured by urgent news. Three days after the battle at Stamford Bridge, on September 28, William of Normandy lands a fleet on the south coast, at Pevensey.

The absence of Harold, away in the north, gives William the luxury of an unopposed landing. He even has time to build himself a makeshift castle before the harassed English king arrives in the south.

The armies meet on a ridge a few miles to the northwest of Hastings. The Normans have the advantage of cavalry and archers. The English, entirely on foot, are armed for long-range combat only with spears and slings. But at close quarters they make devastating use of great two-handed battle axes. These disconcert even the Norman cavalry.

The battle lasts the entire day. In the late afternoon a chance arrow kills Harold (a detail in the Bayeux tapestry is the only evidence for the tradition that it hits him in the eye). The English fight on until nightfall and then disperse. The day is William's. The south of England lies open to him.

The Normans advance on London and meet no opposition until approaching the southern end of London's bridge. William then makes an encircling movement round the city, which yields to him without a siege. On Christmas Day he is crowned in Westminster abbey. The new church has had an eventful first year, with a royal funeral and two coronations.

Norman administration: 1086-1135

In the years after 1066, William secures his new kingdom with exemplary thoroughness. This is a military occupation, so the first requirement is to suppress pockets of resistance. This task is effectively achieved throughout England by 1070. At the same time castles are established from which the nobles of the invading force, serving the king in a network of feudal obligations, can control the kingdom.

Good administration requires efficient taxation. Detailed information about the country is essential. At a court held by the king in Gloucester, during Christmas 1085, a decision is taken to acquire such information.

During 1086 panels of commissioners travel through the counties of England, noting the details of the royal estates and of lands held in fief by vassals of the crown. The entire kingdom is covered as far north as Lancashire and Yorkshire. The only omissions, for reasons unknown, are England's two greatest cities, London and Winchester (at this period serving as joint capitals).

The material is all collected in time to be presented to the king in summarized form in 1087. Known to its contemporaries as the 'description of England', the document acquires the name Domesday Book - comparing it to the Day of Judgement because in both cases the commissioners' findings are final.

Efficient administration of the country continues under William's two sons, William II and Henry I. It is often harsh, but there is a sense of fair dealing. A charter of liberties, issued on the accession of Henry I in 1100, can even be seen as a precursor of Magna Carta a century later. Nevertheless the royal power is steadily extended, particularly through the system pioneered by Henry I of sending the king's judges on circuit round the country to hear cases.

Thus the rapid Norman conquest of England is with equal rapidity made secure. It is celebrated as a fait accompli, probably as early as about 1080, in the magnificent Bayeux tapestry.

But the disastrous accident of the White Ship, in 1120, throws the inheritance into doubt and the country, eventually, into turmoil. It leaves two grandchildren of William the Conqueror as the only contenders for the crown, each of them in some way unsatisfactory. Matilda, the only surviving child of Henry I is in the direct line but is a woman. Her cousin Stephen is male but of a lesser line, being the son of the conqueror's daughter, Adela.

The result, after Henry's death in 1135, is civil war.

Stephen, Matilda and Geoffrey Plantagenet: 1135-1154

Stephen moves rapidly, after the death of his uncle Henry, to stake his claim to the English throne. He crosses immediately from Normandy to England and within a month has himself crowned in Westminster abbey. Meanwhile his agents get to work in Rome. By the following Easter he is able to proclaim that his consecration as king has been confirmed by the pope.

Support for Matilda in England and Normandy would probably be greater were it not for her marriage, in 1128, to Geoffrey Plantagenet. Anjou, the territory to which Geoffrey is heir, has long been a hostile neighbour to Normandy.

In 1139 the pope confirms his judgement in favour of Stephen, prompting Matilda to invade England. A desultory civil war drags on for many years. It is resolved in 1153 in an agreement by which Stephen retains the throne but his heir is declared to be Matilda's son, Henry.

The succession of the prince in 1154, as Henry II, begins the Plantagenet dynasty in England. It also, because of the vast territories which Henry inherits and acquires in France, brings into sharp focus an area of disagreement between the ruling families of the two neighbouring kingdoms.

Lands across the Channel: 11th - 15th century

The Norman conquest of England introduces a new situation in northwest Europe. Lands on both sides of the English Channel are from this time under the control of a single dynasty. The kings of England are also the dukes of Normandy.

A Norman-French royal family crowned in Westminster seeks to extend its territories on the French side of the water. At the same time a Frankish-French royal family crowned in Reims strives to assert its authority over the whole geographical region of France. The result is a prolonged struggle, eventually spanning some four centuries, in which the identities of medieval Europe's two strongest kingdoms are gradually shaped.

The struggle is not just one of warfare and battles. It is a complex game of dynastic marriages and interconnecting obligations. William the Conqueror, king of England, is technically the king of France's vassal - in his other role as the duke of Normandy.

Even more dramatic is the case of William's great-grandson, Henry II. Though a vassal of the French king, his lands occupy a region of France which is larger than the royal domain. The French king rules a realm around Paris and Orleans in the north. Henry II inherits a broad swathe down the entire west of the country.

Henry receives Anjou from his father's family, and Normandy (together with England) through his mother. But his largest holding in continental Europe comes through his marriage to Eleanor of Aquitaine. Henry is her second husband. Her first was the king of France, Louis VII. Were it not for this matrimonial switch, Louis rather than Henry would have secured Eleanor's regions of Aquitaine and Gascony.

In such a manner, in feudal Europe, are territories gained or lost. The major players in this vast board game are the two French dynasties - the Norman French line in England and the Frankish (or Capetian) line in France.

The princes of the two houses marry within the same limited circle, so western Europe becomes an interconnected web of French-speaking cousins - often with good claims to each other's territories. Louis VII and Henry II set a powerful example, as kings of France and England who marry the same heiress from Aquitaine. But the point can be made almost equally well among their successsors.

The kings who follow Henry II on the throne of England marry, in this sequence, daughters of the rulers of Navarre, Angouleme, Provence, Castile, France, Hainaut, Bohemia, Navarre, France and Avignon. During the same period kings of France marry daughters of Navarre, Provence, Castile and Hainaut.

In the long run the advantage lies with the French kings. Geography makes the Channel a natural boundary. A gradual trend away from patchwork feudal territories and towards the cohesive nation state means that eventually the proper place for the English must be north of this boundary.

But the process is a long one, not finally resolved until the end of the Hundred Years' War.